Abnormal IgA glycosylation in Henoch-Schönlein purpura restricted to patients with clinical nephritis

• Published in: Nephrology, dialysis, transplantation dialysis, transplantation, 1998-04, Vol.13 (4), p.930-934
• Main Authors: ALLEN, A. C, WILLIS, F. R, BEATTIE, T. J, FEEHALLY, J
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Amino Acid Sequence; Biological and medical sciences; Child; Child, Preschool; Diseases of the osteoarticular system; Female; Glomerulonephritis, IGA - metabolism; Glycosylation; Humans; Immunoglobulin A - metabolism; Lectins - metabolism; Male; Medical sciences; Middle Aged; Miscellaneous. Osteoarticular involvement in other diseases; Molecular Sequence Data; Plant Lectins; Purpura, Schoenlein-Henoch - metabolism
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/13.4.930

Glomerular deposition of IgA1 is a common feature of Henoch-Schönlein purpura, and is indistinguishable from that seen in IgA nephropathy. Serum IgA1 is abnormally O-glycosylated in IgA nephropathy, and this may contribute to mesangial IgA1 deposition and the development of glomerular injury. This altered O-glycosylation of IgA1 can be detected by its increased binding to the lectin Vicia villosa. To investigate whether IgA1 is abnormally glycosylated in Henoch-Schönlein purpura, the binding of Vicia villosa lectin to serum IgA1 was studied in the following subject groups: IgA nephropathy; adults and children with Henoch-Schönlein purpura and nephritis; children with clinically diagnosed Henoch-Schönlein purpura but no renal involvement; adults and children with non-IgA associated glomerulonephritis; and matched controls. The abnormality of lectin binding seen in IgA nephropathy was also found in both adults and children with Henoch-Schönlein purpura with nephritis. However, the lectin binding of serum IgA1 from children with Henoch-Schönlein purpura lacking renal involvement did not differ from controls, and similarly, no abnormality of lectin binding was seen in patients with non-IgA associated glomerulonephritis. These data indicate that the abnormality of IgA1 O-glycosylation seen in IgA nephropathy is also found in Henoch-Schönlein purpura, but only in those subjects with renal involvement, while IgA1 O-glycosylation is normal in patients with other forms of renal disease. These findings lend strong support to a role for altered IgA1 O-glycosylation in the pathogenesis of IgA-associated glomerular disease.